JP2006102665A - Method and apparatus for treating ammonia in air - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for treating ammonia in the air, in each of which ammonia in the air can be treated efficiently at a low running cost by eliminating a weak point of the conventional method for treating ammonia in the air and the solubility of ammonia in scrubber water is increased to remove ammonia in high efficiency. <P>SOLUTION: The apparatus 10 for treating ammonia in the air is provided with: a scrubber unit 12 in which ammonia in the air is brought into contact with scrubber water to dissolve ammonia in scrubber water; a biological treatment unit 14 in which the ammonia dissolved in scrubber water is treated biologically by a method for oxidizing ammonia anaerobically; and a treated water returning line 62 for returning a part of the treated water treated in the biological treatment unit 14 to the scrubber unit 12 as scrubber water. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The method and apparatus for treating ammonia in the air according to the present invention includes fertilizer factories, livestock industry facilities such as poultry farms and pig farms, compost facilities, sewage treatment plants, human waste treatment plants, garbage disposal facilities, garbage disposal devices, etc. The present invention relates to a method and apparatus for treating ammonia generated from an ammonia generation source.

  Conventionally, the treatment of ammonia diffused into the air from an ammonia generation source such as a livestock industry facility is by dissolving ammonia in scrubber water (for example, using tap water) with a scrubber device, adsorption with activated carbon, decomposition with chemicals, etc. Had been processed. As an apparatus for dissolving ammonia into scrubber water by a scrubber apparatus, for example, there is an apparatus shown in FIG.

  As shown in FIG. 4, while air containing ammonia is introduced from below the deodorization tower 1, scrubber water is sprinkled from the top of the deodorization tower 1, and the air and the scrubber water are brought into contact with each other in the deodorization tower 1. Dissolve ammonia in scrubber water. The scrubber water stored in the storage tank 2 is circulated to the upper part of the deodorization tower 1 by the scrubber pump 3. Conventionally, when ammonia in the air is processed with a scrubber device, acidic water (about pH 2) is circulated to reduce the amount of water used, and the ammonia concentration is concentrated to 3000 to 5000 mg / L to achieve this high concentration. Scrubber wastewater enriched with ammonia was being treated. In addition, by using acidic scrubber water, the gas-liquid contact time can be shortened, thereby making the scrubber device compact. Scrubber water with a neutral pH is also used, but the solubility of ammonia in the scrubber water is reduced and ammonia cannot be concentrated sufficiently, requiring a long contact time, and the equipment is large. There was a problem of becoming.

Also, scrubber water in which ammonia in the air is dissolved is biologically treated by utilizing the ability of microorganisms to decompose. As an in-air ammonia treatment apparatus using biological treatment, for example, there is a nitrification denitrification apparatus disclosed in Patent Document 1. This device introduces a gas to be treated containing ammonia into the nitrification section and sprinkles water from above the nitrification section to dissolve ammonia in the water spray, and all the ammonia passes through nitrous acid by nitrifying bacteria in the nitrification section. Oxidizes to nitric acid. The water spray that has passed through the nitrification unit is stored in the liquid storage unit, and is again circulated to the top of the nitrification unit to be sprayed. The liquid in the liquid reservoir was sent to a denitrification part filled with denitrification bacteria, and while supplying an organic substance (hydrogen donor), nitric acid was converted into nitrogen gas and treated in the denitrification part. The treated water is returned to the liquid reservoir. That is, Patent Document 1 discloses a biology according to a so-called nitrification / denitrification method in which a sprinkling solution in which ammonia is dissolved in a nitrification part having a scrubber mechanism and filled with nitrifying bacteria and a denitrification part filled with denitrifying bacteria. It is an apparatus that treats ammonia in the air by performing a general treatment.
JP 2001-232391 A

  However, when ammonia in the air is dissolved in the scrubber water (sprinkling liquid of Patent Document 1) by the scrubber mechanism, the scrubber water has almost no organic matter, so it is dissolved in the scrubber water by the nitrification / denitrification method as in Patent Document 1. When treated with ammonia, there are the following disadvantages.

  (1) A large amount of methanol is required as an organic substance (hydrogen donor) in the denitrification section, which increases running costs. Incidentally, the amount of methanol used is 2 to 3 times the amount of nitrate nitrogen.

  (2) When a large amount of methanol is used, SS components and hydrogen sulfide are likely to be generated. For this reason, when the treated water from the denitrification part is returned to the liquid storage part and sprinkled on the nitrification part, the sprinkling pipe is easily clogged by the SS component. The generated hydrogen sulfide gas is toxic to the human body, and for safety, it is necessary to install a hydrogen sulfide concentration meter and a facility for removing this hydrogen sulfide.

  (3) When a large amount of methanol is used, excess sludge is generated, and ammonia is generated when the excess sludge is anaerobically treated to reduce the volume. Therefore, an ammonia generation source is generated by the ammonia processing apparatus, and generation of excess sludge becomes a problem when configuring a closed system for ammonia processing.

(4) In order to perform stable treatment in the nitrification / denitrification method of Patent Document 1, the load of the nitrification unit and the denitrification unit is not operated in the range of about 0.2 to 0.3 kg-N / m ³ / day. In other words, the load cannot be increased to treat ammonia at high speed.

  The present invention has been made in view of such circumstances, eliminates the drawbacks of conventional ammonia treatment in air, can efficiently treat ammonia in air at low running cost, It is an object of the present invention to provide a method and apparatus for treating ammonia in the air, which can contribute to improving the environment in the area where ammonia is generated.

  According to a first aspect of the present invention, in order to achieve the object, in the method for treating ammonia contained in the air, the ammonia is dissolved in the scrubber water by a scrubber device that brings the ammonia in the air into contact with the scrubber water. It comprises a scrubber step and a biological treatment step for biologically treating ammonia dissolved in the scrubber water by an anaerobic ammonia oxidation method.

  Here, the biological treatment process by the anaerobic ammonia oxidation method means at least a nitrite type nitrification tank that oxidizes ammonia to nitrite by ammonia-oxidizing bacteria, and simultaneous denitrification of ammonia and nitrite by anaerobic ammonia-oxidizing bacteria. It is the process which made the main structure the anaerobic ammonia oxidation tank.

  In the anaerobic ammonia oxidation tank, ammonia and nitrous acid are simultaneously denitrified by the following reaction formula by anaerobic ammonia oxidizing bacteria using ammonia as a hydrogen donor and nitrous acid as a hydrogen acceptor. References describing the anaerobic ammonia oxidation method include, for example, Strous M et al. (1998) Appl. Microbio Biotechnol. Vol. 50, P589-596.

(Chemical formula 1)
1.0 NH ₄ + 1.32NO ₂ + 0.066HCO ₃ + 0.13H ⁺ → 1.02N ₂ + 0.26NO ₃ + 0.066CH ₂ O _0.5 N _0.15 + 2.03H ₂ O
According to this anaerobic ammonia oxidation method, since ammonia is used as a hydrogen donor, the amount of methanol and the like used for denitrification can be significantly reduced compared to the nitrification / denitrification method, and the amount of sludge generated can be reduced.

  According to the present invention, ammonia in the air is dissolved in the scrubber water by the scrubber device, and the ammonia dissolved in the scrubber water is treated by biological treatment by the anaerobic ammonia oxidation method. The amount of methanol used can be greatly reduced as compared with the case where the treatment is performed by the nitrogen method (Patent Document 1).

  This drastic reduction in the amount of methanol used not only reduces the running cost, but also suppresses the generation of SS components and hydrogen sulfide, so it is inherently due to clogging of the water spray pipe in the scrubber device and the partial pressure of the generated hydrogen sulfide. The ammonia to be dissolved does not become difficult to dissolve in the scrubber water. In addition, the biological treatment by the anaerobic ammonia oxidation method can increase the load compared to the nitrification / denitrification method, so that high-speed treatment of ammonia dissolved in the scrubber water is possible.

  A second aspect of the present invention is characterized in that, in the first aspect, at least a part of the treated water treated in the biological treatment step is used as scrubber water of the scrubber device.

  Since the treated water treated in the biological treatment process contains almost no nitrogen components including ammonia, scrubber water such as tap water can be saved by using the treated water as scrubber water for the scrubber device. In this case, as described above, the anaerobic ammonia oxidation method does not easily generate SS components and hydrogen sulfide, so that the sprinkler pipe of the scrubber device is clogged or naturally generated by the generated hydrogen sulfide, as in the nitrification / denitrification method. The ammonia to be dissolved does not become difficult to dissolve in the scrubber water.

  A third aspect of the present invention is characterized in that, in the first or second aspect, the ammonia concentration of scrubber water to be treated in the biological treatment step is 350 mg / L or less.

The scrubber system circulates scrubber water to reduce waste liquid, and dissolves ammonia in the scrubber water in large quantities. As a result, the concentration of ammonia in the scrubber water increases, resulting in a high concentration of nitrous acid in the biological treatment process. Become. However, while anaerobic ammonia oxidizing bacteria use nitrite as a substrate, the activity decreases when the concentration of nitrite nitrogen (NO ₂ -N) exceeds about 200 mg / L. As can be seen from the above formula, ammonia and nitrous acid react at a ratio of 1: 1.32.

Therefore, if the ammonia concentration of the scrubber water treated in the biological treatment process is 350 mg / L or less, the NO ₂ -N concentration in the anaerobic ammonia oxidation tank does not exceed 200 mg / L, and the anaerobic ammonia oxidizing bacteria The activity can be kept high. The ammonia concentration of scrubber water treated in the biological treatment process can be reduced to 350 mg / L or less by increasing the amount of treated water returned to the scrubber device described in claim 2, for example. Alternatively, the treated water treated in the anaerobic ammonia oxidation tank may be returned to the inlet of the anaerobic ammonia oxidation tank to dilute the nitrous acid concentration of the inflow water flowing into the anaerobic ammonia oxidation tank.

  According to a fourth aspect of the present invention, in order to achieve the above object, in the apparatus for treating ammonia contained in the air, the scrubber apparatus for bringing the ammonia in the air into contact with the scrubber water and dissolving the ammonia in the scrubber water. A biological treatment device that biologically treats ammonia dissolved in the scrubber water by an anaerobic ammonia oxidation method, and a treatment for returning a part of the treated water treated by the biological treatment device as scrubber water of the scrubber device And a water return line.

Claim 4 of the present invention comprises the present invention as an apparatus, in which an anaerobic ammonia oxidation method is performed in a nitrite type nitrification tank and an anaerobic ammonia oxidation tank, and the treated water is used as scrubber water. By doing so, not only can the consumption of tap water be saved, but the NO ₂ -N concentration in the anaerobic ammonia oxidation tank can be kept from exceeding 200 mg / L.

  A fifth aspect of the present invention is the biological treatment apparatus according to the fourth aspect, wherein the biological treatment apparatus distributes the scrubber water in which the ammonia is dissolved into two parts, and substantially all of the ammonia in the one scrubber water thus distributed. A nitrite type nitrification tank that oxidizes to nitric acid, a bypass line that bypasses the other distributed scrubber water and merges with nitrite-containing water treated in the nitrite type nitrification tank, and the merged merge And an anaerobic ammonia oxidation tank that simultaneously denitrifies water by anaerobic ammonia oxidizing bacteria.

  The fifth aspect of the present invention shows an example of an apparatus configuration for suitably obtaining 1: 1.32 which is the ratio of ammonia and nitrous acid in the anaerobic ammonia oxidation method.

  As described above, according to the method and apparatus for treating ammonia in air according to the present invention, it is possible to eliminate the drawbacks of conventional ammonia treatment in air and efficiently treat ammonia in air at low running cost. Since the ammonia removal efficiency can be increased by increasing the solubility of ammonia in water, it can also contribute to the improvement of the environment in which ammonia is generated.

  Preferred embodiments of a method and apparatus for treating ammonia in air according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a first embodiment of an in-air ammonia treatment apparatus of the present invention.

  As shown in FIG. 1, the ammonia treatment apparatus 10 in air mainly includes an scrubber apparatus 12 that contacts ammonia in the air and scrubber water to dissolve ammonia in the scrubber water, and anaerobic ammonia dissolved in the scrubber water. And a biological treatment apparatus 14 for biological treatment by a reactive ammonia oxidation method.

  The scrubber device 12 is mainly composed of a deodorization tower 16 and a storage tank 18, and a circulation pipe 22 including a scrubber pump 20 is disposed from the storage tank 18 to the upper part of the deodorization tower 16, and in the middle of the circulation pipe 22. A water supply pipe 24 for supplying scrubber water such as tap water is connected to the pipe. Thereby, scrubber water is sprinkled from the upper part of the deodorizing tower 16 into the deodorizing tower 16. On the other hand, an air introduction pipe 26 for introducing air containing ammonia into the deodorization tower 16 is connected to the bottom of the deodorization tower 16, and the air treated by the deodorization tower 16 is connected to the top of the deodorization tower 16. A discharge pipe 28 for discharge is connected. As a result, the ammonia-containing air rising from the bottom of the deodorization tower 16 and the scrubber water sprayed from the top of the deodorization tower 16 come into contact, and scrubber water in which ammonia is dissolved in water is generated. The deodorized air is discharged from the discharge pipe 28 to the atmosphere.

  While the scrubber water is stored in the storage tank 18, a pH adjuster is added from the chemical solution addition pipe 30, and the pH of the scrubber water is adjusted to 6.0 to 7.5. As the pH adjuster, phosphoric acid, sodium hydrogen carbonate and the like can be preferably used.

  The biological treatment apparatus 14 mainly includes a distributor 40 that distributes scrubber water stored in the storage tank 18 into two, and a nitrite type that oxidizes substantially all of the ammonia in one of the distributed scrubber waters to nitrous acid. The nitrification tank 32, the bypass pipe 44 for bypassing the other distributed scrubber water to join the nitrite-containing water in the nitrite type nitrification tank 32, and the combined merged water are simultaneously desorbed by anaerobic ammonia-oxidizing bacteria It comprises an anaerobic ammonia oxidation tank 34 for nitriding. That is, the scrubber water stored in the storage tank 18 is sent to the distributor 40 via the raw water pipe 38 by the raw water pump 36 (not necessarily required), and is distributed into two at a predetermined distribution ratio by the distributor 40. The One of the distributed scrubber water is supplied to the nitrite type nitrification tank 32 via the first water supply pipe 42, and the other of the distributed scrubber water is supplied to the anaerobic ammonia oxidation tank 34 via the bypass pipe 44. Water is sent.

  In the nitrite-type nitrification tank 32, ammonia-oxidizing bacteria that oxidize ammonia to nitrous acid are held, and an aeration pipe 48 for aerating air supplied from the blower 46 is provided at the bottom of the tank. As a result, substantially the entire amount of ammonia in the scrubber water distributed to the nitrite type nitrification tank 32 is oxidized to nitrite by the ammonia oxidizing bacteria. The nitrite-containing water treated in the nitrite-type nitrification tank 32 is scrubber water (ammonia-containing) flowing through the bypass pipe 44 while being fed to the anaerobic ammonia oxidation tank 34 via the second water feed pipe 50. Water) and the combined water flows into the anaerobic ammonia oxidation tank 34. Anaerobic ammonia oxidizing bacteria 34 are held in the anaerobic ammonia oxidizing tank 34, and ammonia and nitrous acid are simultaneously denitrified using ammonia as a hydrogen donor by the following reaction formula.

(Chemical formula 2)
1.0 NH ₄ + 1.32NO ₂ + 0.066HCO ₃ + 0.13H ⁺ → 1.02N ₂ + 0.26NO ₃ + 0.066CH ₂ O _0.5 N _0.15 + 2.03H ₂ O
As a method for retaining ammonia-oxidizing bacteria in the nitrite type nitrification tank 32, a carrier or a fixed bed can be preferably used. Examples of the carrier material include polyvinyl alcohol, alginic acid, polyethylene glycol gel, and plastic carriers such as cellulose, polyester, polypropylene, and vinyl chloride, but are not particularly limited. In addition, there are a method of comprehensively immobilizing ammonia-oxidizing bacteria inside the carrier and a method of adhering and immobilizing ammonia bacterium on the surface of the carrier. Either method may be used. For example, in order to produce a carrier in which ammonia-oxidizing bacteria are entrapped and immobilized, heat is applied to a carrier in which complex microorganism sludge containing ammonia-oxidizing bacteria and nitrite-oxidizing bacteria are immobilized, and nitrite oxidation in the complex microorganism sludge is performed. There are ways to inactivate bacteria. In this case, the heat treatment temperature is preferably in the range of 50 to 90 ° C, more preferably in the range of 60 to 80 ° C. As for the shape of the carrier, it is preferable to use a shape obtained by shaping a spherical shape, a cylindrical shape, a porous shape, a cubic shape, a sponge shape, a honeycomb shape, or the like. The fixed bed will be described in detail in a method for holding the anaerobic ammonia oxidizing bacteria described later in the anaerobic ammonia oxidizing tank 34, and is therefore omitted here.

  In the anaerobic ammonia oxidation method, as can be seen from the above reaction formula, ammonia and nitrous acid are supposed to react at a ratio of 1: 1.32. Accordingly, assuming that the nitrification rate in the nitrite type nitrification tank 32 is 100%, the distributor 40 sends about 57% of the ammonia in the scrubber water to the nitrite type nitrification tank 32, and the remaining 43% of the ammonia is supplied. By distributing so that it may send to the bypass piping 44, it becomes possible to adjust the ratio of ammonia and nitrous acid in the combined water which flows into the anaerobic ammonia oxidation tank 34 to 1: 1.32. In the present embodiment, the distributor 40 is used, but the above ratio is obtained by controlling the nitrite type nitrification rate by flowing the entire amount of scrubber water from the storage tank 18 into the nitrite type nitrification tank 32. May be obtained.

  The anaerobic ammonia oxidation tank 34 has a dilution pipe 53 provided with a dilution pump 52 that dilutes the combined water by returning the treated water treated in the anaerobic ammonia oxidation tank 34 to the inlet of the anaerobic ammonia oxidation tank 34. Provided. By diluting the combined water with the dilution pipe 53, the concentration of nitrous acid in the combined water is prevented from exceeding 200 mg / L. This is because nitrite inhibition occurs in the anaerobic ammonia oxidation reaction when the nitrous acid concentration exceeds 200 mg / L.

  Anaerobic ammonia-oxidizing bacteria are retained in the anaerobic ammonia-oxidizing tank 34. The retaining method is preferably the same as the method for retaining ammonia-oxidizing bacteria in the nitrite-type nitrification tank 32 using a carrier or a fixed bed. can do. Since the method using the carrier has been described above, it will be omitted, and the fixed bed will be described here. As a material in the case of using a fixed bed, plastic materials such as polyethylene, polyester, polypropylene, and vinyl chloride, activated carbon fiber, and the like can be used, but the material is not particularly limited thereto. The shape of the fixed floor includes, but is not particularly limited to, a shape shaped like a fiber or chrysanthemum or a shape shaped like a honeycomb. The apparent volume of the fixed bed filled in the anaerobic ammonia oxidation tank 34 is preferably in the range of 30 to 80%, and preferably in the range of 40 to 80%. Moreover, as a porosity, a thing of 80% or more can be used conveniently. In addition to the carrier and the fixed bed, granules using self-granulation of microorganisms can be used in the present invention.

The treated water treated in the anaerobic ammonia oxidation tank 34 is fed through a third water feeding pipe 55 to a denitrification tank 54 that converts nitric acid into nitrogen gas by denitrifying bacteria. In the anaerobic ammonia oxidation method, as can be seen from the above formula, nitric acid (NO ₃ ) is generated although the amount is small. Therefore, in order to completely remove the nitrogen component, it is preferable to denitrify the nitric acid by adding methanol in the denitrification tank 54. In the denitrification tank 54, as described above, a carrier, a fixed bed, or granules for holding microorganisms in the denitrification tank 54 can be used. The nitric acid remaining in the treated water can be easily treated by mixing it with organic waste, and therefore the denitrification tank 54 is not necessarily required and can be omitted.

  The treated water treated in the denitrification tank 54 is sent to the treated water tank 58 via the fourth water supply pipe 56 and stored. A part of the treated water stored in the treated water tank 58 is supplied into the circulation pipe 22 of the scrubber device 12 via the treated water return pipe 62 by the treated water pump 60, and the remaining treated water is discharged from the discharge pipe 64. Is discharged out of the system as waste liquid. By returning a part of the treated water to the scrubber device 12 with the treated water pump 60, the ammonia concentration of the scrubber water sprinkled from the upper part of the deodorizing tower 16 is lower than when the scrubber water in the storage tank 18 is circulated with the scrubber pump 20. can do. Thereby, since the solubility in which the ammonia in the air introduce | transduced into the deodorizing tower 16 is melt | dissolved in scrubber water can be improved, the ammonia concentration in the air discharge | released from the deodorizing tower 16 can be reduced. Moreover, since the ammonia concentration of the scrubber water stored in the storage tank 18 is also low, the nitrous acid concentration in the anaerobic ammonia oxidation tank 34 can be kept low. Therefore, if the concentration of nitrous acid in the combined water flowing into the anaerobic ammonia oxidation tank 34 can be maintained at 200 mg / L or less by returning a part of the treated water to the scrubber device 12 by the treated water pump 60, anaerobic is performed. The dilution pump 52 of the dilution pipe 53 of the basic ammonia oxidation tank 34 may not be operated.

  Thus, according to the ammonia treatment apparatus 10 in the air of the present invention, the scrubber water in which the ammonia in the air is dissolved in the scrubber water by the scrubber apparatus 12 is treated by the biological treatment apparatus 14 by the anaerobic ammonia oxidation method. I made it. Thereby, even if it is scrubber water which hardly contains organic substance, compared with the case where it processes by a nitrification and denitrification method, methanol usage-amount can be reduced significantly. This drastic reduction in the amount of methanol used greatly reduces the generation of SS components and hydrogen sulfide, so the water pipe (not shown) of the deodorization tower 16 is clogged and abnormal hydrogen sulfide is generated. I didn't. Thereby, ammonia dissolution efficiency in the scrubber device 12 can be improved, and ammonia released from the scrubber device 12 into the atmosphere can be reduced as much as possible, which can contribute to improvement of the local environment. In addition, when the ammonia generation source for generating ammonia is a livestock industry facility such as a poultry farm or a pig farm, the breeding environment of animals and the working environment of workers who work can be improved.

In addition, by greatly reducing the amount of methanol used, the generation of excess sludge is greatly reduced compared to the case of treatment by the nitrification / denitrification method. Thereby, since generation | occurrence | production of the excess sludge which is an ammonia generation source can be suppressed by the ammonia process in air, the closed system of an ammonia process can be constructed | assembled. Furthermore, it has been reported that the anaerobic ammonia oxidation method can increase the load to about 8.9 kg-N / m ³ / day, which is twice that of the case where the treatment is performed by the nitrification / denitrification method. Ammonia can be treated by the above high-speed treatment.

  FIG. 2 is a second embodiment of the in-air ammonia treatment apparatus 10 ′ of the present invention. By connecting the storage tank 18 and the denitrification tank 54 with a return pipe 66, the storage tank 18 is connected to the first embodiment. This is a case where the treated water tank 58 shown in the embodiment is also used and a part of the liquid in the storage tank 18 is discharged out of the system as waste liquid. Thereby, since the treated water tank 58 can be omitted, the ammonia treatment apparatus 10 'can be made compact accordingly. Further, similarly to the first embodiment, a treated water pump 60 and a treated water return pipe 62 for returning a part of the treated water treated in the denitrification tank 54 to the scrubber device 12 are provided, and a treated water destination is provided. May be switched to the return pipe 66 and the treated water return pipe 62 by a switch (not shown).

  FIG. 3 shows a third embodiment of the in-air ammonia treatment apparatus 10 ″ according to the present invention, in which treated water treated in the anaerobic ammonia oxidation tank 34 is diverted to the storage tank 18 by the flow divider 68. The treated water is divided into treated water that is diverted to the denitrification tank 54, and the nitric acid remaining in the treated water diverted to the denitrification tank 54 is denitrified by adding methanol and discharged out of the system. In addition, a switching device 72 is provided in the piping 70 between the flow divider 68 and the storage tank 18, and a piping 74 is extended from the switching device 72 to the top of the deodorizing tower 16. Can be sent as scrubber water of the scrubber device 12.

  As a result, the total nitrogen concentration in the treated water discharged out of the system can be reduced, and treated water that has not passed through the denitrification tank 54 is used as the scrubber water of the scrubber device 12, thereby further preventing clogging of the sprinkler pipe. it can. That is, the SS component is generated by adding methanol in the denitrification tank 54, which causes clogging of the water spray pipe, but the treated water that has not passed through the denitrification tank 54 is scrubber water as in the third embodiment. This is because the SS component is not generated in the treated water.

[Comparative Example 1] Case of only scrubber device This is a case where ammonia in the air is treated only by the scrubber device shown in FIG.

(Conditions for scrubber equipment)
· Ammonia (NH ₃₎ concentration of the air introduced into the deodorization tower was an average 143 ppm.
-The flow rate of the air introduced into the deodorization tower was 1 m ³ / min (1440 m ³ / day).
- the volume of the deodorization tower and 0.1m ^3, the residence time of the air introduced was 6 seconds.
-The volume of the storage tank was 1000L.
-The amount of water sprinkled from the top of the deodorization tower by the operation of the scrubbing pump was set to 1 L / min (1440 L / day).
-Tap water was supplied as scrubber water at a supply rate of 200 L / day.

(Test results)
The average ammonia concentration of 143 ppm in the air before being introduced into the deodorization tower was reduced to an average of 5 ppm by treating with a scrubber device. Moreover, the ammonia concentration of the scrubber water in the storage tank was 750 mg / L. Therefore, conventionally, it has been necessary to treat high concentration scrubber water (waste liquid) as much as 200 L / day.

[Example 1]
The ammonia treatment apparatus 10 ′ shown in FIG. 2 described in the second embodiment of the present invention, which combines a scrubber apparatus and a biological treatment apparatus using an anaerobic ammonia oxidation method, was used. The conditions of the scrubber device 12 are the same as those in the comparative example, and the conditions of the biological treatment device 14 are as follows.

(Conditions for biological treatment equipment)
The flow rate of the scrubber water from the storage tank 18 to the biological treatment apparatus 14 was set under the following conditions on the assumption that the ammonia concentration in the scrubber water was 750 mg / L.
The flow rate to the biological treatment apparatus 14 was set to 100 m ³ / day using the raw water pump 36.
-The distribution ratio of the scrubber water by the distributor 40 was distributed so as to be 60% to the nitrite type nitrification tank 32 and 40% to the bypass pipe 44.
The load of the nitrite type nitrification tank 32 was 1.0 kg-N / m ³ / day.
・ The ammonia-oxidizing bacteria retained in the nitrite-type nitrification tank 32 is nitrified by heating a carrier in which a complex microorganism sludge containing ammonia-oxidizing bacteria, nitrite-oxidizing bacteria, etc. is comprehensively immobilized at 60 ° C. for 1 hour. The tank 32 was filled at a filling rate of 15% by volume.
The load of the anaerobic ammonia oxidation tank 34 was 3.0 kg-N / m ³ / day.
The anaerobic ammonia oxidizing bacteria retained in the anaerobic ammonia oxidizing tank 34 was filled with a carrier in which anaerobic ammonia oxidizing bacteria were immobilized and immobilized at a filling rate of 30% by volume. Seed sludge was collected from an apparatus operated to have a denitrification rate of 2.5 kg-N / m ³ / day with a nonwoven fabric as a fixed bed. The collected seed sludge was fixed at a sludge concentration of 1%. The gel used was a polyethylene glycol prepolymer with a gel concentration of 10%.
The circulation rate of returning the treated water from the anaerobic ammonia oxidation tank 34 to the inlet of the anaerobic ammonia oxidation tank 34 by the dilution pump 52 is four times the flow rate of the treated water by the dilution pump 52 than the flow rate of the scrubber water by the raw water pump 36. I tried to become.
The amount of treated water was determined by the flow rate of the raw water pump 36 and was 100 L / day.
The denitrification tank 54 was filled with a fixed bed made of vinyl chloride having a porosity of 85% at an apparent volume of 60%. Moreover, methanol was added so that it might become 200 mg / L.
-Waste liquid was discharged from the storage tank 18 at 100 L / day (overflow discharge).
-To the storage tank 18, while adding phosphoric acid so that the phosphoric acid concentration in the storage tank 18 might be 5 mg / L, 8 g / L of sodium hydrogencarbonate was added.

(Test results)
As a result of stable operation for one month after the acclimatization period of about 3 months, the ammonia concentration of the treated water treated by the biological treatment apparatus 14 is 31 mg / L on average, and the total nitrogen concentration (TN) is 48 mg / L on average. It was greatly reduced as compared with the comparative example.

  The amount of tap water used in the scrubber device 12 is 100 L / day (the rest is circulating the treated water of the biological treatment device 14 to the scrubber device 12), and the amount of tap water used as scrubber water could be halved compared to the conventional amount. . At this time, the total nitrogen concentration (TN) of the scrubber water (waste liquid) in the storage tank 18 was 790 mg / L. Therefore, it was found that the amount of treated water can be halved by carrying out Example 1 of the present invention, although the water quality of the waste liquid does not change.

[Methanol consumption comparison test]
A comparison was made between the amount of methanol used when the scrubber waste liquid was treated with ordinary nitrification / denitrification treatment and with the anaerobic ammonia oxidation method (the present invention).

The experimental conditions were as follows, and a entrapping immobilization support was used for the nitrification step. The entrapping immobilization carrier is obtained by immobilizing activated sludge with a polyethylene glycol-based gel. The gel concentration was 10% by weight and the activated sludge content was 2%. The carrier filling rate was 10%, and the volumetric load on the nitrification tank was 0.8 kg-N / m ³ / day. An apparatus filled with 60% apparent filling rate was used for the denitrification tank. The volume load on the denitrification tank was 0.3 kg-N / m ³ / day. The amount of methanol used was added 3 times the amount of inflowing nitrous acid or nitrate nitrogen.

  As a result, the amount of methanol used for denitrification treatment per liter of scrubber wastewater was 1900 mg / L in the case of conventional nitrification / denitrification treatment, but in the anaerobic ammonia oxidation tank method in the present invention, It was 200 mg / L. Therefore, the amount of methanol used could be reduced to about 1/10. In addition, it was confirmed that the amount of sludge generated was reduced by about 90% from the difference in the amount of methanol used.

  As described above, by using the biological treatment apparatus 14 based on the anaerobic ammonia oxidation method, it is possible to perform ammonia treatment in which the amount of methanol used is greatly reduced. This drastic reduction in the amount of methanol used not only reduced running costs, but also suppressed the generation of SS components and hydrogen sulfide, and the sprinkler pipes in the scrubber device were not clogged and abnormal hydrogen sulfide was not generated. . In addition, the biological treatment by the anaerobic ammonia oxidation method can increase the load compared to the nitrification / denitrification method, so that the scrubber water can be treated at high speed.

[Example 2]
Example 2 is carried out using the ammonia treatment apparatus 10 ″ of FIG. 3 described in the third embodiment of the present invention, which is a combination of a scrubber apparatus and a biological treatment apparatus using an anaerobic ammonia oxidation method. The conditions different from the first embodiment are as follows.
-The flow rate of the raw water pump 36 was 200 L / day.
The diversion ratio between the denitrification tank 54 and the storage tank 18 by the flow divider 68 was set to 1: 1. In Example 2, the switching device 72 was switched to the storage tank 18 side.

  That is, in Example 2, the flow rate to the biological treatment apparatus 14 is twice that of Example 1, half of the treated water in the anaerobic ammonia oxidation tank 34 is sent to the storage tank 18, and the remaining half is sent to the denitrification tank 54. The nitric acid remaining in the treated water was denitrified by feeding and methanol, and then discharged out of the system.

(Test results)
In the case of Example 2, since the treated water sent to the storage tank 18 does not pass through the denitrification tank 54, the SS component is hardly generated in the treated water. Thereby, even if the scrubber water in the storage tank 18 was circulated to the top of the deodorizing tower 16, the water pipe of the deodorizing tower 16 was not clogged. Moreover, as a result of measuring the quality of the treated water discharged out of the system, the total nitrogen concentration (TN) was 60 mg / L, which was greatly reduced as compared with the comparative example.

[Example 3]
Example 3 is a case of using the ammonia treatment apparatus 10 of FIG. 1 described in the first embodiment of the present invention in which a scrubber apparatus and a biological treatment apparatus using an anaerobic ammonia oxidation method are combined. The conditions different from those in Examples 1 and 2 are as follows.
The treated water pump 60 was operated at 500 L / day, and treated water after being treated by the biological treatment device 14 was circulated as scrubber water for the scrubber device 12. That is, in the third embodiment, the treated water of the biological treatment apparatus 14 is not supplied to the storage tank 18 or distributed to the storage tank 18 and the denitrification tank 54 as in the first and second embodiments. The water is sent directly to the scrubber water.

(Test results)
As a result of measuring the ammonia concentration in the storage tank 18, it was 300 mg / L, which was significantly reduced compared to 750 mg / L in Example 1. Furthermore, the ammonia concentration of the air discharged from the deodorizing tower 16 was 1 ppm, which was reduced compared to 5 ppm in the comparative example. This is considered to be because the ammonia concentration in water sprinkled from the deodorizing tower 16 is lowered by using treated water containing almost no nitrogen component as scrubber water, so that the efficiency of dissolving ammonia in water is improved. Furthermore, since the ammonia concentration of the scrubber water in the storage tank 18 is 300 mg / L, the nitrous acid concentration in the combined water flowing into the anaerobic ammonia oxidation tank 34 can be suppressed to 180 mg / L, and the anaerobic ammonia oxidation Processing was possible without operating the dilution pump 52 provided in the tank 34.

The block diagram of 1st Embodiment of the ammonia treatment apparatus in the air of this invention The block diagram of 2nd Embodiment of the ammonia treatment apparatus in the air of this invention The block diagram of 3rd Embodiment of the ammonia processing apparatus in the air of this invention Configuration diagram of a conventional scrubber device for treating ammonia in air

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10, 10 ', 10' '... In-air ammonia treatment device, 12 ... Scrubber device, 14 ... Biological treatment device, 16 ... Deodorizing tower, 18 ... Storage tank, 20 ... Scrubber pump, 22 ... Circulation piping, 24 ... Water Supply pipe, 26 ... Air introduction pipe, 28 ... Release pipe, 30 ... Chemical solution addition pipe, 32 ... Nitrite type nitrification tank, 34 ... Anaerobic ammonia oxidation tank, 36 ... Raw water pump, 38 ... Raw water pipe, 40 ... Distribution , 42 ... first water supply pipe, 44 ... bypass pipe, 46 ... blower, 48 ... aeration pipe, 50 ... second water supply pipe, 52 ... dilution pump, 53 ... dilution pipe, 54 ... denitrification tank, 55 ... first 3, water supply pipe 56, fourth water supply pipe, 58, treated water tank, 60, treated water pump, 62, treated water return pipe, 64, discharge pipe, 66, return pipe, 68, shunt, 70, pipe, 72 ... Switch, 74 ... Piping

Claims (5)

In a method for treating ammonia contained in air,
A scrubber step of dissolving the ammonia in the scrubber water by a scrubber device that contacts the ammonia in the air with the scrubber water;
And a biological treatment step of biologically treating the ammonia dissolved in the scrubber water by an anaerobic ammonia oxidation method.   The method for treating ammonia in air according to claim 1, wherein at least a part of the treated water treated in the biological treatment step is used as the scrubber water.   The ammonia treatment method in air according to claim 1 or 2, wherein the ammonia concentration of scrubber water treated in the biological treatment step is 350 mg / L or less. In a treatment apparatus for ammonia contained in the air,
A scrubber device for contacting ammonia in the air and scrubber water to dissolve the ammonia in the scrubber water;
A biological treatment apparatus for biologically treating ammonia dissolved in the scrubber water by an anaerobic ammonia oxidation method;
A treatment water return line for returning a part of the treated water treated by the biological treatment device as scrubber water of the scrubber device. The biological treatment apparatus comprises:
A distributor that distributes the scrubber water in which the ammonia is dissolved;
A nitrite-type nitrification tank that oxidizes substantially all of the ammonia in the one scrubber water distributed to nitrite;
A bypass line for bypassing the other distributed scrubber water and joining the nitrite-containing water treated in the nitrite type nitrification tank;
The in-air ammonia treatment apparatus according to claim 4, comprising: an anaerobic ammonia oxidation tank that simultaneously denitrifies the merged combined water with anaerobic ammonia oxidizing bacteria.

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